Fireplace damper



M y 6, 1952 A. P. ROBINSON FIREPLACE DAMPER Filed March 7, 1947 INVENTOB flLBE/Zf Pas/man Patented May 6, 1952 UNITED STATES PATENT OFFICE FIREPLACE DAMPER Albert P. Robinson, Seattle, Wash.

Application March 7, 1947, Serial No. 733,042

3 Claims.

This invention relates to fireplace construction and it has reference more particularly to improvements pertaining to certain parts used in the construction of the usual types of residential fireplaces where the masonry or brickwork across the front opening of the fireplace is supported by a metal beam, usually an angle iron, but which may and in many instances comprise a part of a damper frame structure, for example, a structure such asthat disclosed in my United States Patent No. 2,312,000, dated February 23, 1943.

Explanatory to certain features of my invention, it will here be stated that there has always been a certain amount of trouble caused by warping of the beam or other member that supports the masonry across the fireplace opening by reason of its subjection to the intense heat. Warping of this supporting member usually results in cracking the masonry above the opening and sometimes unseats the beam from its supports or otherwise damages the construction.

Also, it will be. mentioned here that due to the difficulty in building up the back wall of the fireplace to exact evenness with the top edges of the side walls, the damper frame, which is designed to rest thereon, may not have proper bearing or be set at the proper level. Either it will be raised too high at the back or there will be an open space left between the lower edge of its back wall and the top of the back wall of the fireplace.

In view of the above, it has been one of the principal objects of this invention to provide means, either as a part of the damper structure or. a part used in combination therewith, for the protection of the masonry bearing member from the effect of the intense heat created in the fireplace, thus to avoid the undesirable warping of the masonry supporting member and the damage to the masonry that is incident to the warping.

Another object of the invention is to provide improvements in details of construction of the back wall of the damper frame construction that will adapt the frame either for support upon the top edge of the back wall of the fireplace or to be disposed against the front face of this wall, thus to make it possible to avoid the difficulties that heretofore have resulted from uneven terminationof the top edges of the back and side walls of the fireplace chamber.

Still further objects of the invention reside in the combination of parts, in their details of construction and mode of use as will hereinafter be fully described.

In accomplishing these and other objects of the invention, I have provided the improved details of construction the preferred forms of which are illustrated in the accompanying drawings, wherein Fig. 1 is a vertical section through a fireplace of typical design, showing a damper housing designed for the support of the masonry across the front of the fireplace opening, and the use of the damper plate as a protective shield for this member.

Figs. 2, 3 and 4, are enlarged cross sectional views of the damper and its frame showin respectively, the damper in fully closed position, a partly open position and fully open.

Fig. 5 is a cross sectional detail showing the mounting trunnion at one end of the damper plate and its application to an opening in the end wall of the damper frame.

Fig. 6 is a perspective view of the damper frame and damper plate as pivotally mounted therein.

Referring more in detail to the drawings In Fig. 1, I have shown, in vertical section. a typical fireplace construction in which the masonry, or brick work that extends across the fireplace opening is supported by the front wall portion of a damper frame or housing that is located in the throat passage of the fireplace leading from the top of the combustion chamber to the flue. The damper housing of that kind shown best in Fig. 6, and is of rectangular form and comprises front and back walls, [9 and H, and opposite end walls l2 and E2. The end walls which are sloped as seen in Fig. 5, have horizontal flanges l3 projecting outwardly from their lower edges, and these rest upon the top surfaces of brickwork that forms the opposite side walls of the combustion chamber as shown in Fig. 5 for the support of the damper housing. The front wall I0, is upwardly and rearwardly sloped and has an integrall cast, horizontal flange I 4 projecting forwardly from its lower edge and there also is a horizontal shelf l5 cast integrally therewith and ertending inwardly from the top of this wall. The flange i4 and the shelf [5 serve to carry the masonry thereon across the top of the fireplace opening best shown in Figs. 1 and 2.

The back wall II of the damper housing is upwardly and forwardly sloped and as noted particularly in Figs. 3 and 4, is somewhat thickened Fig. 4, and is sloped at an angle corresponding to the upward slope of the back wall surface of the fireplace so that it might be engaged flatly against the surface as shown in Figs. 2 and 3 if such should be desired. The forward surface of this thickened portion iii of the back wall H is downwardly curved or rounded and meets the lower edge of the flat surface I! at a sharp edge so as to avoid any abrupt shoulder that would interfere with easy upflow of gases past the wall.

The top of the damper frame is open between the opposite end walls I 2I2' and between the shelf [5 and the back wall i I, and a damper plate 20 is pivotally mounted in the frame for adjustment in this opening between closed position as observed in Fig. 2 and a completely open position as shown in Fig. 4.

A feature of this invention resides in the ar= rangement, manner of mounting and design of the damper plate so that in addition to its use as a damper, it may serve also as a means of protecting the masonry frame supporting portions I 4, l and I5, of the damper frame from the intense fireplace heat that might cause that warping of the frame that results in cracking of the masomy and other damage to the construction.

The damper plate is substantially fiat, and is provided at opposite ends with downwardly directed legs 2| and 2| and trunnions 2222' are extended outwardly from the lower ends of the legs. The trunnions are contained in recesses 23-23 formed in the opposite end walls of the damper frame, as noted in Figs. and 6, and are adapted to rest upon the horizontal flanges l3l3 at the lower edges of these side walls.

The trunnions 2222 have opposite edge surfaces designated in Fig. 3, at 24-24, parallel with their axes adapted to engage the supporting flanges as illustrated in Fig. 3 to balance the damper plate at a partly open position. When tilted rearwardly from this balanced position, the plate will automatically close the damper passage, as in Fig. 2. When tilted from balance in the other direction, it will move to and retain in its full open position at noted inFig. 3.

A lever 25 is applied to the trunnions 22 as seen in Fig. 5, as a means for making these adjustments of the damper plate.

The position of the damper relative to the front wall II! of the damper frame is of prime importance, since it is to act as a heat protective shield for the masonry supporting portion of the frame. Therefore, it is provided that when the damper plate is moved toward open position, for example, to the position of Fig. 3, its forward portion swings down between the fire in the fireplace and the forward wall H] of the frame and flange M. In this position, or any other farther open position an air passage is opened up across the top of the damper plate, and cool air that enters the fireplace just beneath the flange 14 will flow across the plate I U to extract heat therefrom and from the frame members. This has been clearly indicated by the air flow arrows -ain Figs. 3 and 4.

The damper plate is never fully closed except when no fire is burning in the fireplace and therefore the fact that the wall It and fiange I4 are exposed when the daniber is closed, is of no importance.

It is also desirable that the damper plate be equipped on its top side with stops or webs as shown at 26 which will engage with the shelf portion of the damper housing when the damper plate is in a fully open position, thus to prevent the damper plate closing off the air passage between it and the front wall of the frame.

In the construction shown, the masonry support is protected from the fireplace heat by a shielding plate which is so related thereto as to define an air passage through which a flow of cool outside air is induced by the updraft in the flue, and this air has a cooling effect both on the shield and the masonry support, so that no warping of the support, or cracking of the masonry occurs due to this cause.

The particular advantage arising from the design of the back wall H of the damper housing, which has been described and shown particularly in Figs. 2, 3 and 4, resides in the fact that if the back wall of the fireplace should be too high for the housing wall I l to rest directly thereon as in Fig. 4, it can be placed flatly against the front face of this wall as in Fig. 3, regardless of the height of this wall above the side walls on which the frame rests, and in this position there is no abrupt shoulder against which the rising gases and flame of the fire will engage.

Having thus described my invention, what I claim as new therein, and desire to secure by Letters Patent, is:

1. In a fireplace construction; a horizontally disposed rectangular frame comprising front. back and opposit end walls defining the throat passage of the fireplace, said front wall being flanged for support thereon of the masonry across the fireplace opening, a damper plate associated with the frame to control flow of gases upwardly through said passage, and equipped with trunnion supports at its opposite ends pivotally mounted in the end walls of the frame, and about which said plate is adapted to be turned between closed and open positions; said damper plate having a width that is greater than the height of the front wall of the frame and the axial line of said trunnion supports being downwardly offset from the plane of the plate a distanc less than the lateral distance between the trunnion axis and the front wall of the frame whereby the plate when in closed position will be disposed horizontally within the upper end of the said passage, and when turned to a forwardly and downwardly inclined position to open the passage, will be moved bodily toward the front wall of the frame and disposed in inclined position adjacent thereto to extend above and below it as a protective shield against fireplace heat and will provide a relatively wide open passage at the back side thereof for the upflow of hot gases through the throat passage.

2. In a fireplace construction; a horizontally disposed rectangular frame comprising front, back and opposite end walls defining the throat passage of the fireplace; said front wall serving as a support for th masonry across the top of the front opening of the fireplace, a damper plate associated with the frame to control upflow of gases through the passage, and equipped with trunnion supports at its opposite ends pivotally mounted in the end walls of the frame, and about which said plate is adapted to be turned between passage closing and passage opening positions; the axial line of the trunnion supports being downwardly offset from the plane of the plate a distance less than the lateral distance between the trunnion axis and the front wall of the frame whereby the plate, when in passage closing position will be disposed horizontally within the upper end of the passage and when turned to open position will be moved toward the front wall of the frame and downwardly, and will be disposed in an inclined position adjacent thereto as a protective shield therefor against fireplace heat, and by this movement will provide a relatively wide open passage at the back side of the plate for the upflow of hot gases through the throat passage, and an air passage at the front side thereof for upflow of cooling air entering from the top of the fireplace opening.

3. A structure as recited in claim 2 wherein the front wall of the said frame is equipped at top and lower edges with flanges for the support thereon of the masonry across the front opening of the fireplace, and said trunnion supports are mounted in the end walls of the frame near their lower edges, and said damper plate has a width that is substantially greater than the height of the said front wall, and when moved to its inclined, open position extends below and above the planes of the masonry supporting flanges of the said front wall, and serves to defleet inflowing cool air to the passage at the front side of the plate.

ALBERT P. ROBINSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,578 Roberts Apr. 30, 1840 650,050 Phenice May 22, 1900 926,048 Champion June 22, 1909 1,224,516 Tyler May 1, 1917 1,410,138 Tandy Mar. 21, 1922 FOREIGN PATENTS Number Country Date 610,285 Germany Mar. 8, 1935 

